Bag design: each filter bag with a zipper, the zipper is plastic, so it 't rust and harm fish health, it is very ventilate for fish to stay inside for its mesh grids, convenient to fill and empty bags, not easy for fish to escape Wide range of usage: it is suitable for filtering fine, charcoal media and smaller particle media, it is available for aquarium, swimming pool, pond and any other occasions Quality material: The media filter bag is made of corrosion-resistant Polyester material, breathable and not easy to break, you for a long time usage; the mesh will not be blocked , improving the water quality and filter media usage time and efficiency. Place the mesh bag containing the filter media in the aquarium to keep the aquarium clean and clean. Suitable canister filters, power filters, wet/ dry filters, swimming pool and pond. Number of package: the package include 20 pieces white filter bags, 20 pieces black filter bags, 40 pieces aquarium filter bags in total, enough for your usage in Color: black and white Material: Polyester Size: . 15 x 20 cm/ 6 x 7.9 inches Mesh hole size: . 2 mm/ 0.08 inch Package Contents: 40 x Filter Bags Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.